Fitbit is an American company headquartered in San Francisco, California, known for its products of the same name, which are activity trackers, wireless-enabled wearable technology devices that measure data such as the number of steps walked, heart rate, quality of sleep, steps climbed, and other personal metrics involved in fitness. The first product released was the Fitbit Tracker. Some evidence has found that the use of similar devices results in less weight loss rather than more.